Disposable and reusable filter cartridges are employed in a number of applications requiring fluid-filtration. In such applications, it is desirable for the filter cartridges to be easily removed from the associated mounting structures for purposes of replacement with fresh/clean filter cartridges. Furthermore, during use, the mounting structures are typically required to form a fluid-tight seal at the ends of the filter cartridge so that the fluid passes through the filtration media forming the cylindrical wall of the cartridge. Thus, any successful filter cartridge mounting assembly needs to mount the filter cartridge so as to form a fluid-tight seal without damaging the filter cartridge's ends.
Several proposals exist in the art to accomplish the purposes stated above. For example, in U.S. Pat. Nos. 5,028,327 to Ostreicher et al and 4,731,184 to Ostreicher et al, filter elements have a gasket which forms a seal with an edge of an inverted cup-shaped element. The cup-shaped element is apparently held in sealing contact with the gasket by means of a compression spring. Various threaded means have also been used in prior art mounting structures so as to secure a filter cartridge within a canister as can be seen, for example, form U.S. Pat. Nos. 3,442,390 to Petrucci et al, 3,546,853 to Claar, and 4,759,845 to Selesnick.
While the prior art proposals mentioned above are satisfactory, there still exists the need for improvement, especially in terms of cartridge sealing and removal efficiencies. It is towards supplying such a need that the present invention is directed.
Broadly, the present invention is embodied in a novel sealing device associated with a mounting assembly for filter cartridges. In this regard, the sealing device of the present invention includes a sealing bolt having a threaded shank portion for being threadably engaged with one (upper) end of an interior apertured cartridge support post. A head portion of the bolt allows it to be turned manually by a suitable tool to assist in threadably interconnecting the shank and post. The other (lower) end of the support post is rigidly connected (e.g., via welding) to a lower external sealing cup-flange which sealingly bears against the lower end gasket associated with the filter cartridge.
The sealing bolt is provided with an upper sealing cup-flange positioned concentrically around the shank portion immediately below the head portion of the sealing bolt. An O-ring seal is embedded in the lower surface of the head portion so as to sealingly bear against the upper sealing cup-flange when the sealing bolt is threadably tightened with respect to the support post. Furthermore, the upper cup-flange is maintained in close proximity, but with slight clearance space (e.g., less than about 1/16"), to the O-ring seal by means of a stationary retaining ring seated in an annular groove in the shank portion of the sealing bolt. Therefore, the upper sealing cup-flange is allowed to move freely around the shank portion of the sealing bolt, but is positionally maintained along the sealing bolt's length-wise axis by the retaining ring.
In such a manner, the sealing bolt is threadably interconnected easily with the support post and tightened sufficiently to form fluid-tight seals between the peripheral edge of the upper sealing cup-flange and the upper gasket of the filter cartridge, as well as between the O-ring embedded in the head portion and an adjacent surface portion of the upper sealing cup-flange. Furthermore, since the lower sealing cup-flange and support post constitute an integrally rigid structure, tightening of the sealing bolt will cause the peripheral edge of the lower sealing cup-flange to be compressed into fluid-tight sealing engagement with the lower gasket of the filter cartridge. Thus, the fluid-tight seals are achieved according to the present invention without damaging the filter cartridge's ends.
Further aspects and advantages of this invention will become more clear after careful consideration is given to the detailed description of the preferred exemplary embodiments thereof which follows.